This invention relates to material handling apparatus, and more particularly, it concerns a portable hoist of the type which may be securable to the side rails of a conventional pickup truck.
In various operations a need exists for material handling apparatus capable of lifting up to approximately one-half ton. For example, home builders require hoisting apparatus to load and unload lumber and other materials, to hoist roof trusses in place, to hoist roofing materials, to hoist bricks and mortar, to set I-beams, and for many other operations. A general home building contractor does not wish to invest a large sum of money either in the rental or purchase of a self-propelled derrick or crane vehicle. Further, such crane vehicles generally have a load carrying capacity which greatly exceeds the loads which would be encountered in general home building. Further, in activities such as sign installation, general warehouse moving, farming, and boat launching and storage, high load carrying capacities are not required. Operators not having the need for large, self-propelled equipment would prefer to purchase or rent a hoist readily adaptable to a conventional pickup truck, while at the same time retaining the use of the truck for other purposes.
Heretofore, several truck mounted arrangements have been available having a limited hoisting or lifting capacity. For example, U.S. Pat. No. 3,797,672 to Vermette, entitled APPARATUS ATTACHABLE TO A TRUCK BODY OR THE LIKE FOR USE FOR HOISTING OR LIFTING, OR AS AN ELEVATED SUPPORT, issued Mar. 19, 1974, discloses a device having a frame attachable to stake holes of a pickup truck and supporting a single, vertically extending boom. Attached to the top of the boom is a cross member to which a cable hoist is secured. The boom is collapsible in a forward direction to permit transportation of the apparatus. This arrangement, however, while resulting in unobstructed use of the bed of the pickup truck, is limited in the area that can be reached by the hoist hook. Further, no provision is made for increasing the stability of the assembly during hoisting operation.
U.S. Pat. No. 2,541,970 to Pospisil entitled "THREE-LEG TRUCK MOUNTED DERRICK," issued Feb. 13, 1951, discloses a portable derrick arrangement which permits hoisting only from the rear of a truck body. This apparatus does not permit hoisting from points around the sides as well as the back of the vehicle.
Therefore, a need exists for a collapsible boom and derrick hoist assembly mountable on a pickup truck or other such vehicle and possessing complete roadability, the ability to elevate a load, and having a hook swing or reach permitting operation around the sides of the transportation vehicle.